Checkbox has values of 0 and -1?

Question

I have some checkboxes on my webapp, and a save button. When I click the save button, I save the checked state of the checkboxes to the database.

When the checkboxes are not checked, I get 0's in the database. However, when they are checked, I get -1's in the database. I was expecting 1's. Are the -1's normal for checked states?

Sample code:

Function ProcessAction(ByVal checkbox1 As Integer, ByVal checkbox2 As Integer) As Integer

    connection = New SqlConnection(ConfigurationSettings.AppSettings("connString"))

    command = New SqlCommand("stored_procedure_name_here", connection)
    command.CommandType = CommandType.StoredProcedure

    command.Parameters.Add(New SqlParameter("@id", SqlDbType.Int, 4)).Value = 100
    command.Parameters.Add(New SqlParameter("@checkbox1", SqlDbType.Int, 4)).Value = checkbox1
    command.Parameters.Add(New SqlParameter("@checkbox2", SqlDbType.Int, 4)).Value = checkbox2

    command.Connection.Open()
    command.ExecuteNonQuery()
    command.Connection.Close()

    Return 1
End Function

The call:

Sub ButtonClick(ByVal Source As Object, ByVal E As EventArgs)
    ProcessAction(checkbox1.Checked, checkbox2.Checked)
End Sub

David M · Accepted Answer · 2013-03-13T13:56:49.090

3

A lot will depend on the code in between, but a Boolean true value is conventionally represented as the integer value -1. It all depends on how you are handling the value before it gets persisted. Some code would be useful if you need further help.

EDIT: The code added shows you are relying on an implicit cast from Boolean to integer, resulting in this -1 value. In VB, depending on the version, you could use Iif(checkbox1.Checked, 1, 0) or If(checkbox1.Checked, 1, 0). Alternatively, keep the value as a Boolean, and save to the appropriate underlying DBMS data type if there is one - for example, in SQL Server, this would be a bit data type.

edited Mar 13 '13 at 13:56

answered Mar 13 '13 at 13:29

David M

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You have already converted to int value -1 by the time you call this method ... show us the calling code... – David M Mar 13 '13 at 13:48
So, you are implicitly casting a boolean (`checkbox1.Checked`) to an integer, resulting in the value `-1`. If you want any other value, you need to do this explicitly. – David M Mar 13 '13 at 13:55
Is there a `proper` or `better` way to do this. Sounds like I should really be saving the actual boolean values directly to the db instead of integers? – oshirowanen Mar 13 '13 at 13:57
[SQL Server doesn't actually have a boolean data type](http://msdn.microsoft.com/en-us/library/ms187752.aspx). But you can use a BIT type (0, 1, or NULL). – criticalfix Mar 13 '13 at 14:57
1

Not exactly, no, it doesn't. But `bit` remains the appropriate underlying data type for a Boolean value for SQL Server. Didn't claim it was _actually_ a Boolean data type... ;) – David M Mar 13 '13 at 15:35

score 1 · Answer 2 · edited May 23 '17 at 10:32

1

These would be true and false values in .NET, but the database may represent those values differently. For instance, Access uses -1 as a "true" value.

edited May 23 '17 at 10:32

Community

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answered Mar 13 '13 at 13:36

criticalfix

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score 0 · Answer 3 · answered Mar 13 '13 at 15:01

0

I think u need to use code like below

    Sql = CheckBoolean(Checkbox.checked)
Function CheckBoolean(Value As Boolean)
    If Value Then Return "-1"
    Return "0"
End Function

answered Mar 13 '13 at 15:01

KaZzA

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Checkbox has values of 0 and -1?

3 Answers3